Corrosion of iron in 1 M HCl solutions containing benzhydrazide derivatives with two terminal adsorption groups as additives

• V.P. Grigor’ev¹, E.V. Plekhanova² and L.D. Popov¹

¹ Southern Federal University, ul. Zorge 7, Rostov-on-Don, 344090 Russian Federation
² Don State Technical University, Gagarin sq. 1, Rostov-on-Don, 344000 Russian Federation

Abstract: The rate of corrosion of iron in 1 M HCl at different concentrations C of benzhydrazide additives was determined in a wide range of solution temperatures. The values of corrosion inhibition coefficients K under the conditions studied are insignificant and in some cases practically do not depend on the inhibitor concentration in the solution. An explanation is provided for these facts on the basis of the influence on these compounds of the structure and nature of the two adsorption groups in the molecule of the compounds studied and allowance for their possible vertical position during the adsorption on the surface of the iron sample. The effective activation energies of Fe corrosion in 1 M HCl inhibited by benzhydrazide derivatives were determined. They were found to be independent on the inhibitor concentration. Based on the specificity of the structure of the investigated compounds (two adsorption centers) and the possible formation of a solution layer saturated with fragments of adsorbed inhibitors, the independence of activation energy W on inhibitor concentration with increasing inhibitor concentration is explained. The values of W correspond to the mixed diffusion-kinetic control of Fe dissolution under the conditions studied and are close to the values of W reported in literature for the dissolution of Fe in HCl.

Keywords: inhibitor, corrosion, corrosion inhibition coefficient, adsorption

Int. J. Corros. Scale Inhib., 2018, 7, no. 3, 409-417 PDF (403 K)
doi: 10.17675/2305-6894-2018-7-3-10

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